Serum antibody titers in urethritis and chronic bacterial prostatitis.

Serum antibody titers were measured by direct bacterial agglutination technique against various strains of Escherichia coli found in the fecal flora of a control group of men who had no history of genitourinary tract infection, against the strains of E. coli responsible for urethral infection in 7 men with urethritis, and against the strains of E. coli responsible for prostatic infection in 25 men with chronic prostatitis. Low serum titers were found in both the control group (median titer of 1:20) and in the urethritis group (median titer of 1:10). Excluding 3 men who had self-agglutinating strains, 18 of 22 (82 per cent) in the prostatitis group had serum titers of 1:320 or greater (median titer of 1:640). Measurement of serum antibody titers by this technique can be a valuable adjunct to diagnosis in cases of chronic prostatitis due to strains of E. coli.